There exists a need for the removal of unwanted hair to maintain desired personal appearance. There are many different devices known in the art that are useful for removing unwanted hair, such as razors, tweezers, and depilatory devices.
Although razors provide quick and easy hair removal, hair remains visible at the surface of the skin and quickly regrows. Therefore one must shave frequently in order to maintain smooth skin and a desired appearance. Tweezers also may be used. Prior art tweezers comprise two arms that are resiliently biased away from each other, each arm having an opposing surface. The hair is positioned between the two opposing surfaces, and the arms are pressed together, thereby grasping the hair between the two opposing surfaces of the tweezer arms. The hair is then plucked from the body. Tweezers provide longer-lasting hair removal. However, removing hair with tweezers is a tedious process since traditional tweezers can only remove one hair at a time. In addition, precise handling is required in order to position and grasp the hair between the two, usually small, opposing surfaces. In addition, because the hair is forcibly pulled from the skin, this is a painful process.
Alternatively, permanent depilatory devices may be used. These devices use high frequency electricity to destroy hair-producing papilla at the base of the hair shaft. However, many of these devices involve large and expensive equipment, and therefore require a visit to a salon and an appointment with a skilled operator. However, salon visits can be expensive and inconvenient since many people do not have the time to make regular visits. In addition, salon visits do not provide the privacy many people would like. Therefore, there is a need for a simple, convenient device that may be operated safely, effectively, and privately.
One of the well-known techniques for hair removal involves high frequency coagulation of the root of the hair. According to this technique, a needle is inserted into a follicle adjacent to the unwanted hair in order to reach the matrix area which contains the hair-producing papilla. High frequency electrical waves are then applied by the needle to the matrix area or papilla, thereby destroying it. Frequently, these devices include a tweezer used to pull the hair out of the follicle once the matrix area or papilla has been destroyed. These types of devices are illustrated in U.S. Pat. No. 3,054,405 to Tapper, U.S. Pat. No. 2,894,512 to Tapper, and U.S. Pat. No. 853,096 to Lewis. There are several drawbacks to these devices. Even with a skilled operator, patients may be cut or burned by the needle. The insertion of the needle under the skin is invasive and painful, particularly in tender skin areas, and may produce irritation, swelling, and burning of the skin tissues. In addition, only one hair can be treated and removed at a time. Accordingly, the removal of hair is a painful, uncomfortable, and tedious process, particularly where large areas of hair are to be removed.
More recently, there has been increasing use of a hair removal device using a tweezer with two arms that serve as electrodes. The tweezer arms are squeezed together to grip the hair at a considerable distance from the skin, and the electrode arms are charged with high frequency electrical current that flows along the hair shaft to its root.
The electrical current then coagulates the root, destroying the hair, which may then be removed. Such devices are shown in U.S. Pat. No. 2,888,927 to Fozard, U.S. Pat. No. 2,417,530 to Weiser, and U.S. Pat. No. 1,071,978 to White.
In addition, there are prior art devices which utilize radio frequency energy or current to coagulate the root of the hair. Specifically, U.S. Pat. No. 4,274,413 to Hahn discloses a depilatory tweezer, wherein the tweezer alms function as electrodes. To use this device, a hair is gripped precisely between the electrically conductive surfaces of the electrodes, and radio frequency is applied to the hair to bring about the coagulation of its root. In addition, U.S. Pat. No. 4,174,713 to Mehl discloses a hair removal device that applies concentrated radio frequency energy to a hair, thereby inducing conduction along the internal section of the hair shaft and downwardly to the matrix area to permanently damage the hair.
All of the devices described above require electric current to pass through the hair shaft in order to successfully effect hair destruction. However, there are problems with such devices. For example, in the tweezer electrode design described above, the electrodes may easily come into contact with each other when the tweezer arms are squeezed together (as with, for example, very fine hairs), thereby short circuiting the device, in which case electricity will not pass through the hair shaft. In order to ensure a complete circuit through the hair, the hair has to be grasped precisely between the tweezer electrodes. In addition, because hair is not a good conductor of electricity, the electrical energy has to be sufficiently high to induce conduction through the hair and destruction of the matrix area. In addition, the electrodes have to be held on the hair close to the skin to ensure that the high frequency energy reaches the matrix area. Unless the root is sufficiently coagulated, unwanted hair may reappear.
Such high frequency electrical energy must be kept away from the skin to prevent damage to the skin. Even in the hands of a skilled operator, there is danger of the electrode touching the skin, which will burn and sometimes scar the skin.
Since the above methods remove only one hair at a time, they are tedious and time consuming even when applied to small skin areas.
None of the depilatory devices discussed above provides for a device having a completed electric circuit before engaging the hair. The designs described above require the hair to complete the circuit. In one embodiment of the present invention, by contrast, radio waves are applied to the hair through a coil spring that is placed proximal to or in contact with the hair. This design overcomes the aforementioned difficulties of the prior art devices.